This thesis contains three chapters on international trade. The first chapter focuses on how international trade affects a country’s innovation. Based on the novel dataset, the results show a significant and positive relationship between trade with China and the innovation outcomes of Korean manufacturing firms. This relationship is stronger for large or public firms than for SMEs (Small and medium-sized enterprises) or private firms. The results also show that firms in the high-quality sector are more likely to overcome competition from trade through innovation than firms in the low-quality sector. The second chapter analyzes how exchange rate volatility affects international trade. Empirical evidence shows the positive association between exchange rate volatility and export trade. Additional analysis reveals that the impacts vary by the level of income and financial development of the trading partners. The third chapter provides an analysis of how trade facilitation measurements affect SME exports in developing countries. The result shows that reducing export times at borders boosts the exports of both SMEs and large firms in developing countries. It suggests the potential benefit of trade facilitation measures on SMEs’ exports.